Dirt Bike Engine
Dirt Bike Engine Parts at JJ Motorsports
Discover a full range of dirt bike engine components for rebuilding or upgrading your performance from JJ Motorsports. From crankshafts to cylinder heads and piston kits, these precision-engineered components ensure reliable performance. For additional upgrades, check out our full selection of off-road dirt bike parts to keep your engine running at peak efficiency on the track or trails.
Shop trusted brands like Wiseco for forged piston kits and K&N for high-flow oil filters. Explore related categories such as Dirt Bike Air and Fuel for intake upgrades or Dirt Bike Exhaust for complete systems.
Browse our in-stock inventory below with same-day shipping and expert support. Questions? Contact us for fitment advice!
- Product
- Qty in Cart
- Quantity
- Price
- Subtotal
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Wossner Piston Kit Yamaha YZ450F 2020-2022 8965DA
WOSSNER
$224.00If you're running hard on the track or pushing your YZ450F to its limits in competition, piston durability and throttle response are non-negotiable. The Wossner Piston Kit delivers the precision engineering and material science that separates competitive...09106142- SKU:
- 09106142
- Availability:
- Ships Same Business Day
- Weight:
- 0.71 LBS
- BORE - OVERSIZE:
- STANDARD
- MODEL:
- PREMIUM SERIES
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- BORE - OVERSIZE METRIC:
- STANDARD
- BORE SIZE METRIC:
- 97.00 MM
- COMPRESSION RATIO IMPERIAL:
- 13.2:1
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- PISTON SIZE METRIC:
- 96.96 MM
- PRODUCT NAME:
- PISTON KIT
$224.00Qty in Cart: 0Quantity:Price:$224.00Subtotal: -
Wossner Piston Kit Yamaha YZ450F 2003-2004 8562DA
WOSSNER
$194.00If you're running a YZ450F hard—whether on the track or in practice—piston failure isn't an option. The Wossner 8562DA gives you the durability and reliability needed to push your bike to its limits without compromise. Built with German engineering and...09106148- SKU:
- 09106148
- Availability:
- Ships Same Business Day
- Weight:
- 0.71 LBS
- PISTON MATERIAL:
- FORGED
- PISTON SIZE METRIC:
- 94.96 MM
- BORE SIZE METRIC:
- 95.00 MM
- MODEL:
- STANDARD SERIES
- RIDING STYLE:
- OFF-ROAD
- BORE - OVERSIZE:
- STANDARD
- BORE - OVERSIZE METRIC:
- STANDARD
- COMPRESSION RATIO IMPERIAL:
- 12.5:1
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- KIT
$194.00Qty in Cart: 0Quantity:Price:$194.00Subtotal: -
Wossner Piston Kit Suzuki RM-Z450 2013-2025 12.5:1 CR 8886DB
WOSSNER
$204.00When you're pushing your RM-Z450 to the limit, factory pistons become your weakest link. The Wossner 12.5:1 Compression Ratio Piston Kit delivers the durability and precision engineering needed to handle aggressive riding and high-RPM demands, while the...09106152- SKU:
- 09106152
- Availability:
- Ships Same Business Day
- Weight:
- 0.91 LBS
- BORE - OVERSIZE:
- +0,01 MM
- BORE SIZE METRIC:
- 95.51 MM
- COMPRESSION RATIO IMPERIAL:
- 12.0:1
- PRODUCT NAME:
- PISTON KIT
- BORE - OVERSIZE METRIC:
- +0.01 MM
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- PISTON SIZE METRIC:
- 95.47 MM
- MODEL:
- STANDARD SERIES
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$204.00 -
Wossner Piston Kit Honda CRF450R 2009-2012 13.4:1 8768DA
WOSSNER
$214.00A worn or stock piston limits your CRF450R's ability to maintain consistent power under load, leading to increased blow-by and reduced efficiency. The Wössner 8768DA replaces those limitations with a precision-engineered forged piston that delivers...09106153- SKU:
- 09106153
- Availability:
- Ships Same Business Day
- Weight:
- 0.86 LBS
- BORE SIZE METRIC:
- 96.00 MM
- PRODUCT NAME:
- PISTON KIT
- BORE - OVERSIZE METRIC:
- STANDARD
- COMPRESSION RATIO IMPERIAL:
- 13.4:1
- ENGINE TYPE:
- 4-STROKE
- MODEL:
- PRO SERIES
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- PISTON SIZE METRIC:
- 95.96 MM
- BORE - OVERSIZE:
- STANDARD
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$214.00Qty in Cart: 0Quantity:Price:$214.00Subtotal: -
Wossner Piston Kit Honda CRF 450 R 2013-2014 8880DA
WOSSNER
$204.00The stock piston in your Honda CRF 450 R can become a limitation when you're pushing harder on the track or trail. Wossner's purpose-built piston kit delivers the strength and reliability needed for sustained high-performance riding, with engineering...09106154- SKU:
- 09106154
- Availability:
- Ships Same Business Day
- Weight:
- 0.71 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- PISTON SIZE METRIC:
- 95.96 MM
- BORE - OVERSIZE:
- STANDARD
- BORE - OVERSIZE METRIC:
- STANDARD
- BORE SIZE METRIC:
- 96.00 MM
- COMPRESSION RATIO IMPERIAL:
- 12.5:1
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- PISTON KIT
- MODEL:
- STANDARD SERIES
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$204.00Qty in Cart: 0Quantity:Price:$204.00Subtotal: -
Wossner Piston Kit Honda CRF450R 2017-2025 95.95mm 13.5:1 8936DA
WOSSNER
$204.00The Wossner Piston Kit is engineered to restore or exceed your CRF450R's power output while delivering the durability required for sustained high-RPM operation. A complete piston replacement addresses wear that reduces compression, throttle response, and...09106157- SKU:
- 09106157
- Availability:
- Ships Same Business Day
- Weight:
- 0.85 LBS
- BORE - OVERSIZE:
- STANDARD
- BORE SIZE METRIC:
- 96.00 MM
- PRODUCT NAME:
- PISTON KIT
- COMPRESSION RATIO IMPERIAL:
- 13.5:1
- MODEL:
- PREMIUM SERIES
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- BORE - OVERSIZE METRIC:
- STANDARD
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- PISTON SIZE METRIC:
- 95.95 MM
$204.00 -
Wossner Piston Ring Set KTM 450 EXC-F 2012-2025 RIK95.00
WOSSNER
$48.50Piston ring degradation directly impacts combustion efficiency, compression loss, and overall engine reliability—especially in high-stress racing environments. The Wossner Piston Ring Set RIK95.00 is engineered to restore optimal sealing characteristics...09120860- SKU:
- 09120860
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- PRODUCT NAME:
- PISTON RING SET
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 95.00 MM
- RIDING STYLE:
- STREET
$48.50 -
Wossner Piston Ring Set Honda CRF450R 2005-2020 Kawasaki KX450F 2006-2018 RIK96.00E
WOSSNER
$48.50When you're rebuilding a high-revving four-stroke dirt bike engine, piston ring quality directly impacts compression, power delivery, and engine longevity. The Wössner Piston Ring Set RIK96.00E is precision-engineered to maintain optimal cylinder sealing...09120861- SKU:
- 09120861
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- PRODUCT NAME:
- PISTON RING SET
- RIDING STYLE:
- ATV
- UNITS:
- EACH
- PISTON SIZE METRIC:
- 95.96 MM
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 96.00 MM
- PISTON SIZE METRIC:
- 95.97 MM
$48.50 -
Wossner Piston Ring Set Yamaha YZ450F 2020-2025 RIK97.00
WOSSNER
$48.50When your YZ450F is pushing peak RPM, worn piston rings bleed compression and power. The Wossner Piston Ring Set RIK97.00 restores the seal your engine needs to deliver full combustion efficiency, whether you're chasing lap times or conquering technical...09120862- SKU:
- 09120862
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- BORE SIZE METRIC:
- 97.00 MM
- PRODUCT NAME:
- PISTON RING SET
$48.50Qty in Cart: 0Quantity:Price:$48.50Subtotal: -
WSM Power Valve Rubber Boot 010-495-05
WSM
$18.53A worn or damaged power valve boot directly impacts your exhaust tuning precision—compromising the responsiveness and peak performance you've dialed in. The WSM Power Valve Rubber Boot 010-495-05 is a direct-fit replacement that restores proper exhaust...09500473- SKU:
- 09500473
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- TYPE:
- POWER VALVE
- UNITS:
- EACH
- RIDING STYLE:
- WATERCRAFT
- PRODUCT NAME:
- BOOT
$18.53 -
WSM Power Valve Piston 010-495-10
WSM
$16.34Exhaust gas scavenging and intake timing are critical to unlocking your engine's full potential, especially in high-RPM applications where fractional gains compound into measurable power increases. The WSM Power Valve Piston 010-495-10 optimizes your...09500474- SKU:
- 09500474
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- RIDING STYLE:
- WATERCRAFT
- PRODUCT NAME:
- PISTON
- TYPE:
- POWER VALVE
- UNITS:
- EACH
$16.34 -
MOOSE RACING Crankcase Bearing and Seal Kit 24-1022
MOOSE RACING
$53.95A worn or damaged crankshaft bearing compromises engine reliability and performance—especially critical in 2-stroke engines where bearing failure can cause catastrophic damage. The MOOSE RACING Crankcase Bearing and Seal Kit 24-1022 delivers...A241022- SKU:
- A241022
- Availability:
- Ships Same Business Day
- Weight:
- 0.55 LBS
- PRODUCT NAME:
- BEARING KIT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- RIDING STYLE:
- STREET
- TYPE:
- CRANK
$53.95 -
MOOSE RACING Washer/Snap Ring Counter Shaft 25-6012
MOOSE RACING
$26.95Front sprocket replacements require more than just swapping out the sprocket itself—you need reliable fastening hardware to ensure the countershaft stays secure under load. The MOOSE RACING Washer/Snap Ring Counter Shaft 25-6012 provides the...09350492- SKU:
- 09350492
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- SNAP RING
- APPLICATION:
- COUNTERSHAFT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- 10 PACK
$26.95 -
Twin Air Oil Filter Yamaha WR250F WR250R WR250X WR450F YZ250F YZ250FX YZ450F YZ450FX 140017
TWIN AIR
$11.95Engine protection starts with filtration. A quality oil filter removes contaminants that compromise lubrication and accelerate wear on internal components—especially critical for high-revving four-stroke dirt bikes and race machines. The Twin Air 140017...140017- SKU:
- 140017
- Availability:
- Ships Same Business Day
- Weight:
- 0.08 LBS
- RIDING STYLE:
- ATV
- TYPE:
- CARTRIDGE
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- OIL FILTER
- FILTER MEDIA MATERIAL:
- PAPER
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- STYLE:
- STANDARD
$11.95 -
On Sale
PROX Valveshim - 10.00 x 2.60 - 5 pack 29.100260
PROX
MSRP: $9.95Now: $8.00Was: $9.95Valve shims are critical wear items in high-lift, high-RPM engines where precision clearance directly impacts valve timing and engine longevity. The PROX Valveshim 10.00 x 2.60 delivers OEM-equivalent performance at a fraction of the cost, making it an...09261005- SKU:
- 09261005
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- SHIM KIT
- TYPE:
- VALVE
- UNITS:
- 5 PACK
- OUTSIDE DIAMETER METRIC:
- 10.00 MM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- STREET
- VALVE SHIM THICKNESS METRIC:
- 2.60 MM
MSRP: $9.95Now: $8.00Was: $9.95 -
On Sale
PROX Valveshim - 10.00 x 2.65 - 5 pack 29.100265
PROX
MSRP: $9.95Now: $8.00Was: $9.95Valve shim wear is one of the most common causes of valvetrain noise and loss of performance in high-revving engines. The PROX Valveshim delivers OEM-equivalent precision at a fraction of the cost, allowing you to maintain exact valve clearances without...09261006- SKU:
- 09261006
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- TYPE:
- VALVE
- PRODUCT NAME:
- SHIM KIT
- UNITS:
- 5 PACK
- OUTSIDE DIAMETER METRIC:
- 10.00 MM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- STREET
- VALVE SHIM THICKNESS METRIC:
- 2.65 MM
- RIDING STYLE:
- OFF-ROAD
MSRP: $9.95Now: $8.00Was: $9.95Qty in Cart: 0Quantity:Price:MSRP: $9.95Now: $8.00Was: $9.95Subtotal: -
On Sale
PROX Valveshim - 10.00 x 2.70 - 5 pack 29.100270
PROX
MSRP: $9.95Now: $8.00Was: $9.95Valve shims are critical wear items that directly impact your engine's valve clearance, compression ratio, and overall performance consistency. PROX Valveshims deliver precision-engineered replacements at a fraction of OEM costs, making them the smart...09261007- SKU:
- 09261007
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- OUTSIDE DIAMETER METRIC:
- 10.00 MM
- TYPE:
- VALVE
- VALVE SHIM THICKNESS METRIC:
- 2.70 MM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- STREET
- PRODUCT NAME:
- SHIM KIT
- UNITS:
- 5 PACK
- RIDING STYLE:
- OFF-ROAD
MSRP: $9.95Now: $8.00Was: $9.95 -
On Sale
PROX Valveshim - 10.00 x 2.75 - 5 pack 29.100275
PROX
MSRP: $9.95Now: $8.00Was: $9.95Valve shim maintenance is critical to engine performance and longevity, yet OEM replacements come with premium pricing that adds up quickly across multiple shims. The PROX Valveshim 10.00 x 2.75 delivers precision-engineered durability at a fraction of...09261008- SKU:
- 09261008
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- TYPE:
- VALVE
- RIDING STYLE:
- OFF-ROAD
- OUTSIDE DIAMETER METRIC:
- 10.00 MM
- VALVE SHIM THICKNESS METRIC:
- 2.75 MM
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- STREET
- UNITS:
- 5 PACK
MSRP: $9.95Now: $8.00Was: $9.95 -
On Sale
PROX Valveshim - 10.00 x 2.80 - 5 pack 29.100280
PROX
MSRP: $9.95Now: $8.00Was: $9.95Valve shim wear directly impacts engine timing precision and performance—especially critical in high-revving builds where tolerance stacking compounds over time. PROX Valveshims deliver OEM-equivalent durability at a fraction of the cost, making them the...09261009- SKU:
- 09261009
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- TYPE:
- VALVE
- VALVE SHIM THICKNESS METRIC:
- 2.80 MM
- OUTSIDE DIAMETER METRIC:
- 10.00 MM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- STREET
- UNITS:
- 5 PACK
MSRP: $9.95Now: $8.00Was: $9.95 -
On Sale
PROX Valveshim - 10.00 x 2.85 - 5 pack 29.100285
PROX
MSRP: $9.95Now: $8.00Was: $9.95Valve shim replacement is one of the most routine maintenance tasks in performance engine building, and using quality OEM-equivalent parts directly impacts your engine's longevity and reliability. The PROX Valveshim 10.00 x 2.85 delivers...09261010- SKU:
- 09261010
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- OUTSIDE DIAMETER METRIC:
- 10.00 MM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- STREET
- VALVE SHIM THICKNESS METRIC:
- 2.85 MM
- PRODUCT NAME:
- SHIM KIT
- TYPE:
- VALVE
- UNITS:
- 5 PACK
- RIDING STYLE:
- OFF-ROAD
MSRP: $9.95Now: $8.00Was: $9.95
